U.S. patent application number 11/213217 was filed with the patent office on 2006-03-02 for electrical plug with a slidable earth pin.
This patent application is currently assigned to Astec International Limited. Invention is credited to Gurmeet S. Bhutani.
Application Number | 20060046539 11/213217 |
Document ID | / |
Family ID | 35198585 |
Filed Date | 2006-03-02 |
United States Patent
Application |
20060046539 |
Kind Code |
A1 |
Bhutani; Gurmeet S. |
March 2, 2006 |
Electrical plug with a slidable earth pin
Abstract
An electrical plug is disclosed with a slidable earth pin that
can be manually positioned in a stored position in a plug body of
the electrical plug when the electrical plug is not in use. The
slidable earth pin is movable in the channel and retained by an
interlocking mechanism between the earth pin and the channel on the
plug body. The earth pin has a pair of protruding fingers that snap
into a first set of grooves in the channel of the plug body in a
first position, and that snap into a second set of grooves in the
channel of the plug body in a second or stored position. When the
earth pin is in its stored position, the physical dimension of the
plug is significantly more compact than conventional three pin
plugs.
Inventors: |
Bhutani; Gurmeet S.; (Pasig,
PH) |
Correspondence
Address: |
NIXON PEABODY, LLP
401 9TH STREET, NW
SUITE 900
WASHINGTON
DC
20004-2128
US
|
Assignee: |
Astec International Limited
|
Family ID: |
35198585 |
Appl. No.: |
11/213217 |
Filed: |
August 25, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60605793 |
Aug 30, 2004 |
|
|
|
Current U.S.
Class: |
439/103 |
Current CPC
Class: |
H01R 24/30 20130101;
H01R 2103/00 20130101; H01R 13/652 20130101; H01R 27/00
20130101 |
Class at
Publication: |
439/103 |
International
Class: |
H01R 13/648 20060101
H01R013/648 |
Claims
1. An electrical plug, comprising: a first conductive blade; a
second conductive blade; a slidable earth pin having an earth pin
blade, a first finger and a second finger; and a plug body
including a channel having a first left snap groove and a first
right snap groove for positioning said earth pin in a first
position, and having a second left snap groove and a second right
snap groove for positioning said earth pin in a second position;
wherein the slidable earth pin is manually movable in said channel
between said first and said second positions.
2. The electrical plug of claim 1, wherein when the slidable earth
pin is in said first position, an interlocking mechanism is formed
between the slidable earth pin and the plug body by a compressive
force asserted by each of said fingers, such that said first finger
is retained in the first left snap groove and said second finger is
retained in the first right snap groove.
3. The electrical plug of claim 1, wherein when the slidable earth
pin is in said second position, an interlocking mechanism is formed
between the slidable earth pin and the plug by a compressive force
asserted by each of said fingers, such that said first finger is
retained in the second left snap groove and said second finger is
retained in the second right snap groove.
4. The electrical plug of claim 1, wherein the earth pin comprises
an edge stop for ensuring that the earth pin is inserted a
predetermined distance and no farther into an electrical
socket.
5. The electrical plug of claim 1, wherein said earth pin fingers
have sliding contact surfaces for sliding in said channel and
wherein each said finger asserts a force against the sides of said
channel of a predetermined amount to maintain a selected level of
sliding friction between said earth pin and said plug body.
6. The electrical plug of claim 1, wherein the first left snap
groove and the first right snap groove hold the earth pin in place
after insertion unless a force is applied to the earth pin that is
greater than a specified safety norm.
7. An electrical plug, comprising: a first conductive blade; a
second conductive blade; a slidable earth pin having an earth pin
blade, a first finger and a second finger, said first finger having
a first set of finger locks and said second finger having a second
set of finger locks, and the first and second fingers having a slot
between the first and second finger locks; and a plug body
including a channel having upper mating grooves for positioning
said earth pin in a first position, and having lower mating grooves
for positioning said earth pin in a second position for storing
said slidable earth pin in said plug body; wherein the slidable
earth pin is manually movable in said channel between said first
and said second positions.
8. The electrical plug of claim 7, wherein when the slidable earth
pin is in said first position, an interlocking mechanism is formed
between the slidable earth pin and the plug body by a compressive
force asserted by each of said fingers, such that said first set of
finger locks is retained against a ledge in the upper mating
grooves.
9. The electrical plug of claim 7, wherein when the slidable earth
pin is in said second position for storing, an interlocking
mechanism is formed between the slidable earth pin and the plug by
a compressive force asserted by each of said fingers locks, such
that each of said second finger locks is retained in the lower
corresponding mating grooves.
10. The electrical plug of claim 9, wherein the earth pin comprises
an edge stop for ensuring that the earth pin is inserted a
predetermined distance and no farther into an electrical socket.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. provisional
application Ser. No. 60/605,793 filed Aug. 30, 2004.
FIELD OF INVENTION
[0002] The invention relates generally to electrical plugs and more
particularly to electrical plugs having movable earth pins.
BACKGROUND OF THE INVENTION
[0003] A wide variety of electrical devices typically draw AC power
from a commercial source, usually delivered through a wall
receptacle or socket, via a corresponding electrical plug.
[0004] A conventional electrical plug typically has a pair of
conductive power pins for insertion into corresponding female
connectors in the socket. The plug typically also includes an earth
or ground pin that is inserted into a corresponding female
connector in the socket that is coupled to ground. In one or more
countries, the earth pin is slightly longer than the power pins and
also functions to open a spring loaded shutter in the socket, to
allow insertion of the power pins into their respective female
connectors in the socket. This safety feature thus requires that an
earth pin be included in all plugs even when there is no need for a
ground connection.
[0005] Battery chargers comprise one type of electrical device
whose plugs typically do not require an earth or ground connection.
However, to provide the shutter opening function, a dummy ground
pin still needs to be provided. Such prior art earth pins are
usually in a fixed position on the electrical plug, which makes the
electrical plug unnecessarily bulky.
[0006] One prior art method for repositioning the earth pin in an
electrical plug is to connect the earth pin to a hinge, to enable
the pin to be rotated between two positions, an open position and a
stored position. The pin is rotated 90.degree. between these two
positions about the axis of the hinge.
[0007] Consumers of electrical products in recent times have shown
a desire for more compact designs. Accordingly, there is a need to
reduce the amount of space taken up by an electrical plug when not
in use, to enable the plug to be more compact.
SUMMARY OF THE INVENTION
[0008] The present invention describes an electrical plug with a
slidable earth pin that can be moved into the body of the
electrical plug when the electrical plug is not in use. The
electrical plug has a slidable earth pin that is positioned in a
channel formed in the plug body. The earth pin has a pair of
fingers that snap into a first set of grooves in the channel of the
plug body to position the earth pin in a first or functional
position. The pair of fingers can also snap into a second set of
grooves in the channel of the plug body to position the earth pin
in a second or stored position. When the earth pin is slid into its
stored position, the physical dimension of the electrical plug is
significantly reduced, thereby providing a more convenient and
compact electrical plug.
[0009] Broadly stated, an electrical plug according to the present
invention comprises a plug body, a first conductive blade; a second
conductive blade; an earth pin having a first finger and a second
finger; a channel having a first left snap groove and a first right
snap groove for enabling the earth pin to be retained in a first
position, and having a second left snap groove and a second right
snap groove for enabling the earth pin to be retained in a second
position; and wherein the earth pin can be slidably positioned such
that said fingers can be manually positioned in respective first
snap grooves or in respective second snap grooves. In one
embodiment, the earth pin is not removable with a force less than a
specified safety norm after the earth pin has been inserted.
Advantageously, the present invention provides an electrical plug
design that reduces the physical dimension of the electrical plug
when not in use.
[0010] Other structures and methods regarding the present invention
are disclosed in the detailed description below. This summary does
not purport to define the invention.
[0011] These and other embodiments, features, aspects, and
advantages of the invention will become better understood with
regard to the following description, appended claims and
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIGS. 1A-1B illustrates perspective views of a slidable
earth pin plug in accordance with a first embodiment of the present
invention.
[0013] FIG. 2A illustrates a sectional view of the slidable earth
pin plug in a first or functional position; and FIG. 2B illustrates
a sectional view of the slideable earth pin plug in a second or
stored position of the earth pin in accordance with the first
embodiment of the present invention with the front panel
removed.
[0014] FIG. 3 illustrates the assembly of the slidable earth pin
plug in accordance with the first embodiment of the present
invention with the front panel removed.
[0015] FIGS. 4A-4B are detailed perspective views respectively
illustrating the slidable earth pin and its sliding contact fingers
and the assembly of the slidable earth pin plug in accordance with
the first embodiment of the present invention.
[0016] FIG. 5A is a detailed perspective view illustrating an earth
pin and its sliding contact fingers for a slidable earth pin plug
in accordance with a second embodiment of the present invention;
FIG. 5B is a perspective rear view and 5C is a rear view
illustrating the earth pin of FIG. 5A assembled in the slidable
earth pin plug in accordance with the second embodiment of present
invention with the back panel removed.
[0017] FIGS. 6A-6B are respective side and front views of the
slidable earth pin plug in accordance with the first embodiment of
the present invention.
[0018] Reference symbols or names are used in the figures to
indicate certain components, aspects or features therein, with
reference symbols common to more than one figure indicating like
components, aspects of features shown therein.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0019] Referring now to FIGS. 1A-1B, there are shown perspective
views of a slidable earth pin plug 100 in accordance with a first
embodiment of the present invention. The slidable earth pin plug
100 comprises a plug body 110, a slidable earth pin 120, including
an earth pin blade 124, and a pair of conductive blades 140. The
slidable earth pin 120 is manually slidable in a vertical direction
in a channel 115 formed in the plug body 110 between the pair of
conductive blades 140, as indicted by an arrow 150 in FIG. 1B.
[0020] The slidable earth pin 120 in plug 100 can be manually
displaced from a first or "functional" position to a second, stored
position, as shown in FIGS. 2A and 2B, respectively. In its first
position, the slidable earth pin 120 is in a position where the top
end of the earth pin 120 protrudes from the plug body 110 a
sufficient distance to enable the earth pin blade 124 to be in a
functional position, i.e., where it can be inserted into a
corresponding female connector in a socket at the same time, or in
advance of when the conductive blades 140 are inserted into similar
corresponding female connectors in the socket, all as specified by
the plug/socket standards of the country in which the plug is to be
used. In its stored position, the entire length of the slidable
earth pin 120 is preferably within the channel 115 and inside the
plug body 110 so that the slidable earth pin 120 does not protrude
beyond a top surface 111 of the plug body 120 or beyond the bottom
surface 112 of the plug body 120.
[0021] FIGS. 2A-2B also illustrate the means by which earth pin 120
is releasably retained at its respective first and second
positions. Earth pin 120 includes first and second fingers 121 and
122 that are compressed slightly when earth pin 120 is first
inserted into channel 115, as described in greater detail below. In
its first position, as shown in FIG. 2A, earth pin 120 is retained
in channel 115 by a first left snap groove 130a wherein the first
finger 121 is positioned, and by a first right snap groove 130b
wherein the second finger 122 is positioned, such that the earth
pin 120 interlocks with the plug body 110. When the electrical plug
100 is not is use, the earth pin 120 can be manually pushed down
the channel 115 to a second or stored position, as shown in FIG.
2B, and held in place by the operation of the first finger 121
snapping into a second left snap groove 135a and the second finger
122 snapping into a second right snap groove 135b.
[0022] Note that, in its second or stowed position, earth pin 120
provides an indication that an attempted insertion of plug 100 into
a socket is incorrect. That is, in its second position, earth pin
120 protrudes out from plug body 110 in the direction of conductive
blades 140 in a position that will not align with a socket's ground
pin socket hole, thereby preventing the insertion of plug 100 into
the socket when earth pin 120 is in this position.
[0023] As seen in the views of the present invention shown in FIGS.
1 and 2, earth pin 120 is prevented from being pushed to a position
below the point where first and second fingers 121 and 122 snap
into second left and right grooves 135a and 135b because of the
existence of a narrowing in a slot 126 formed at the front of
channel 115. This narrowing is perhaps best seen at 128 in FIG. 3.
Consequently, as the earth pin 120 is pushed down the slot, the
bottom surface of the earth pin blade 124 makes contact with
surface 129 of slot 126, thereby preventing further travel of the
earth pin 120 down channel 115.
[0024] As is seen in FIGS. 2A and 2B, fingers 121 and 122, as well
as left and right grooves 130a and 130b include surfaces that
enable fingers 121 and 122 to be moved out of these grooves with a
modest amount of manual force applied to the earth pin 120 in the
desired direction of travel.
[0025] In FIG. 3, there is a pictorial diagram illustrating a step
in the assembly of the slidable earth pin plug 100 wherein the
earth pin is first inserted into channel 115. In this step, earth
pin plug 100 is being inserted into the channel 115 of the plug
body 110, either manually with hand pressure or using a tool or
fixture. Once inserted, the upper surfaces of grooves 130a and 130b
may be shaped in a conventional way known in the art to make it
difficult for the earth pin 120 to thereafter be removed from
channel 115 in a direction opposite to the direction of
insertion.
[0026] As perhaps better seen in FIG. 3, channel 115 includes two
sets of snap grooves, a first set comprising first left snap groove
130a and first right snap groove 130b, and a second set comprising
second left snap groove 135a and second right snap groove 135b. The
narrowing of slot 126 in the area shown at 128 creates ledges
129.
[0027] A detailed perspective view illustrating earth pin 120 of
the first embodiment of the present invention is shown in FIGS. 4A
and 4B. As seen in these figures, earth pin 120 includes a vertical
section 125 that terminates in fingers 121 and 122 (i.e., the
sliding contact surface area) for sliding in the channel 115 of the
plug body 110. The compressive force of fingers 121 and 122 along
the sides of channel 115 is selected so as to maintain a preferred
level of sliding friction in moving the earth pin 120 up and down
channel 115. The earth pin 120 can even be inserted at a vendor as
part of the post-moulding operation. Side and front views of the
electrical plug 100 are shown in FIGS. 6A and 6B.
[0028] In FIGS. 4A-4B, there are shown perspective views of an edge
stop 170 that is preferably formed on the top surface of earth pin
120. This surface 170 is positioned to ensure that an end user
inserts the earth pin 120 a predetermined distance into an
electrical outlet (not shown), and no farther.
[0029] Turning now to FIG. 5A, there is shown a detailed
perspective view illustrating an earth pin 500 and its first and
second sliding contact fingers according to a second embodiment of
the present invention. FIG. 5B and 5C illustrate the slidable earth
pin plug with the rear removed to show the structurally different
aspects of earth pin 500 as compared to earth pin 120 described
above. The earth pin 500 of the second embodiment is designed with
a dual lock approach, where each of the sliding contact fingers has
a first set of finger locks 510 that is parallel to a second set of
finger locks 512. The first set of finger locks 510 is used for
locking the earth pin 500 in slot 515 by means of ledges 518 of the
upper mating grooves 522, as seen in FIG. 5B. The purpose of the
first set of finger locks 510 is to prevent the earth pin 500 from
popping out of a plug body 550 after the earth pin 500 has been
inserted into the slot 515 in plug body 550. The second set of
finger locks 512, as seen in FIG. 5C, is used for positioning the
earth pin 510 in either a folded position or an unfolded position,
as well as providing the user with an indication of proper fitting
between the earth pin 500 and the plug body 550 by the sounding of
a click when the second set of finger locks 512 has been mated with
upper mating grooves 522 or with lower mating grooves 524. A slot
514 in the earth pin 500 is provided to impart flexibility to an
arm 530 having the second set of finger locks 512.
[0030] In a third embodiment of the present invention, the earth
pin 120 or 500 is not removable with a force less than a specified
safety norm after the earth pin 120 or 500 has been inserted. The
finger locks 122 and the grooves 130a and 130b in the first
embodiment, and the finger locks 510 and the ledges 518 in the
second embodiment are designed to implement this safety feature of
the third embodiment.
[0031] In a preferred embodiment, earth pin 120 or 500 is a
non-conductive dummy pin for use in a battery charger or the like
where there is no need for a ground connection but where the earth
pin 120 or 500 is just needed to open the spring loaded shutter of
the socket in which the plug is to be inserted. One of the ordinary
skill in the art should recognize that the present invention can be
applied to different types of electrical plugs in various regions
or countries. One suitable application is on plugs as used in the
United Kingdom.
[0032] Those skilled in the art can now appreciate from the
foregoing description that the broad techniques of the embodiments
of the present invention can be implemented in a variety of forms.
Therefore, while the embodiments of this invention have been
described in connection with particular examples thereof, the true
scope of the embodiments of the invention should not be so limited
since other modifications, whether explicitly provided for by the
specification or implied by the specification, will become apparent
to the skilled practitioner upon study of the drawings,
specification, and following claims.
* * * * *